Haiti's presidential palace and numerous other government buildings in the country's capital Port-au-Prince collapsed on Tuesday after a massive 7.0 earthquake, Haitian television, streaming online, reports.

Communications to the island, the most impoverished country in the Western hemisphere, were cut in the wake of the massive earthquake, which produced several aftershocks and prompted a tsunami warning.

A journalist with Haitian television station Haitipal, interviewed by telephone from Port-au-Prince, told the station that public buildings across the capital had been destroyed.

"The presidential palace, the finance ministry, the ministry of public works, the ministry of communication and culture [were all affected by the quake]," the reporter said, adding that the Parliament building and a cathedral in the capital were also crumbling.

Residents were buried under the rubble, a Reuters reporter in the city said.

He said he saw dozens of dead and injured people in the rubble, which blocked streets in the city.

The epicentre of the quake was located inland, only 16 kilometres from Port-au-Prince and was very shallow at a depth of only 10 kilometres.

It prompted a tsunami watch for parts the Caribbean, the Pacific Tsunami Warning Centre said.